Ocean Fertilisation a No-Go - New Research Says

Back in February Richard Branson launched the Virgin Earth Challenge, where twenty-five million dollars has been put on the table, available to anyone that can come up with a plan to save the planet from climate change doom. I've often seen websites promoting one particular geo-engineering scheme above others as a prime candidate for this prize -- ocean fertilisation (by the way, 'geo-engineering' simply translates to our adjusting our planet's systems/mechanisms to accommodate our lifestyles, as opposed to changing our lifestyles to work within natural systems - a couple of several posts we've done on this are here and here).

For those not familiar, ocean fertilisation has the aim of reducing CO2 in the atmosphere by stimulating algae blooms. By adding nutrients like microscopic iron particles to the ocean, CO2-absorbing plankton are stimulated into a frenzy of activity. Eventually some die and sink to the ocean depths, taking the CO2 with them. There have been limited small experiments done in this area over the last decade or so, but they have been very well hyped.

Although it all sounds good in theory, there has been considerable concern within and without governments and science labs around the world. Amongst the potential side-effects (at least those that are known, or perceived), are the risks of having the kind of toxic blooms that have become major issues in some of the world's lakes and rivers:

Models have predicted that long-term fertilization of the oceans could result in hypoxia and anoxia in the deep ocean which would increase microbial production of greenhouse gases such as methane and nitrous oxide. This would set off a rapid warming of the earth, leading to increased stratification of the oceans which would slow the biological pump, and negate any probable short-lived human benefits. - MarSci

Adding to these fears, today it was announced that a more intimate look at how ocean systems work demonstrates that algae blooms and sinking CO2 do not go hand in hand:

Ocean Fertilization 'Fix' For Global Warming Discredited By New Research

Research performed at Stanford and Oregon State Universities suggests that ocean fertilization may not be an effective method of reducing carbon dioxide in the atmosphere, a major contributor to global warming....

...this process, which is analogous to adding fertilizer to a lawn to help the grass grow, only reduces carbon dioxide in the atmosphere if the carbon incorporated into the algae sinks to deeper waters. This process, which scientists call the "Biological Pump", has been thought to be dependent on the abundance of algae in the top layers of the ocean. The more algae in a bloom, the more carbon is transported, or "pumped", from the atmosphere to the deep ocean.

To test this theory, researchers compared the abundance of algae in the surface waters of the world's oceans with the amount of carbon actually sinking to deep water. They found clear seasonal patterns in both algal abundance and carbon sinking rates. However, the relationship between the two was surprising: less carbon was transported to deep water during a summertime bloom than during the rest of the year. This analysis has never been done before and required designing specialized mathematical algorithms.

"By jumping a mathematical hurdle we found a new globally synchronous signal," said Dr. Lutz.

"This discovery is very surprising", said lead author Dr. Michael Lutz, now at the University of Miami's Rosenstiel School of Marine and Atmospheric Science. "If, during natural plankton blooms, less carbon actually sinks to deep water than during the rest of the year, then it suggests that the Biological Pump leaks.

More material is recycled in shallow water and less sinks to depth, which makes sense if you consider how this ecosystem has evolved in a way to minimize loss", said Lutz. "Ocean fertilization schemes, which resemble an artificial summer, may not remove as much carbon dioxide from the atmosphere as has been suggested because they ignore the natural processes revealed by this research."

... There is no point trying to ameliorate the effects of climate change by destroying the oceans -- the very cradle of life on earth. Simply doing more and bigger of that which has already been demonstrated to be ineffective and potentially more harmful than good is counter-intuitive at best.'

Indeed, the global study of Dr. Lutz and colleagues suggests that greatly enhanced carbon sequestration should not be expected no matter the location or duration of proposed large-scale ocean fertilization experiments.

According to Dr Lutz "The limited duration of previous ocean fertilization experiments may not be why carbon sequestration wasn't found during those artificial blooms. This apparent puzzle could actually reflect how marine ecosystems naturally handle blooms and agrees with our findings. A bloom is like ringing the marine ecosystem dinner bell. The microbial and food web dinner guests appear and consume most of the fresh algal food."